AutoCodes – Generic – B1521

B1521 Code - Hood Switch Circuit Short To Battery

Quick Answer

The Body Control Module (BCM) monitors the Hood Switch. Common causes include Faulty Hood Switch, Hood Switch harness is open or shorted, Hood Switch circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: B1521 indicates Hood Switch Circuit Short To Battery.
Common causes: Common causes include Faulty Hood Switch, Hood Switch harness is open or shorted, Hood Switch circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 9,012

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 29, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B1521 Description

The Body Control Module (BCM) monitors the Hood Switch. The BCM sets the OBDII code when the Hood Switch is not to factory specifications.

OBDII Code B1521 - Hood Switch Circuit Short To Battery - AutoCodes.com — B1521 Code - Hood Switch Circuit Short To Battery

What does this mean?

What are the Possible Causes of the DTC B1521?

Faulty Hood Switch
Hood Switch harness is open or shorted
Hood Switch circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B1521?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B1521 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the B1521 code?

Need more information on how to fix the B1521 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B1521 code diagnosed by a professional: Find a repair shop in your area

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B1521 Code

1. What are the common symptoms of OBDII code B1521 (Hood Switch Circuit Short To Battery)?

- The common symptoms include the hood ajar warning light staying illuminated even when the hood is closed, the vehicle's alarm system being triggered intermittently, and issues with remote start functionality.

2. What can cause the OBDII code B1521 to trigger?

- The code B1521 is typically triggered when there is a short circuit between the hood switch circuit and the battery, which can be caused by damaged wiring, a faulty hood switch, or a problem with the hood latch mechanism.

3. How can I diagnose the cause of OBDII code B1521?

- To diagnose the cause of B1521, you can start by visually inspecting the hood switch wiring and connector for any damage or corrosion. You can also test the hood switch for continuity and check the hood latch mechanism for proper operation.

4. Can I drive my vehicle with OBDII code B1521 present?

- It is generally safe to drive your vehicle with the B1521 code, but you may experience issues with the alarm system, remote start, or other related functions. It is recommended to address the issue promptly to prevent further problems.

5. How can I repair OBDII code B1521?

- Repairing the B1521 code involves fixing the short circuit in the hood switch circuit. This may include repairing or replacing damaged wiring, replacing the faulty hood switch, or adjusting the hood latch mechanism to ensure proper contact with the switch.

6. Is it possible to reset OBDII code B1521 without fixing the issue?

- While you can clear the code temporarily with an OBDII scanner, it is important to address the underlying issue causing the code to prevent future problems with the vehicle's alarm system and other related functions.

7. Can a DIY enthusiast fix OBDII code B1521 at home?

- Yes, a DIY enthusiast with basic automotive repair skills can attempt to fix the B1521 code at home by following the diagnostic steps, identifying the cause of the issue, and repairing or replacing the faulty components as needed.

8. Does the OBDII code B1521 affect the overall drivability of the vehicle?

- The B1521 code itself does not affect the drivability of the vehicle, but it may lead to issues with the alarm system, remote start, or other related functions. It is best to address the code promptly to maintain the vehicle's proper operation.

9. Are there any preventive measures to avoid OBDII code B1521 in the future?

- To prevent the recurrence of the B1521 code, it is essential to perform regular inspections of the hood switch wiring, connectors, and latch mechanism for any signs of wear or damage. Keeping these components in good condition can help avoid future issues.

10. Is it necessary to visit a dealership for OBDII code B1521 repair?

- While visiting a dealership is an option, you can also choose to work with an independent mechanic or address the B1521 code yourself if you have the necessary tools and skills. The key is to diagnose the issue accurately and carry out the repairs effectively.